Vortex core magnetization dynamics induced by thermal excitation

TL;DR

This paper studies how finite temperature affects magnetic vortex dynamics in small disks, revealing thermally induced vortex precession and the influence of temperature gradients, using a stochastic LLG equation approach.

Contribution

It introduces a stochastic LLG model to analyze temperature effects on vortex dynamics, highlighting thermally induced precession and gradient effects.

Findings

Finite temperature causes vortex precession without external excitation.

Temperature gradients mimic small magnetic fields affecting vortex behavior.

The stochastic LLG approach effectively models thermal effects in magnetic vortices.

Abstract

We investigate the effect of temperature on the dynamic properties of magnetic vortices in small disks. Our calculations use a stochastic version of the Landau-Lifshitz-Gilbert (LLG) equation, valid for finite temperatures well below the Curie critical temperature. We show that a finite temperature induces a vortex precession around the center of the disk, even in the absence of other excitation sources. We discuss the origin and implications of the appearance of this new dynamics. We also show that a temperature gradient plays a role similar to that of a small constant magnetic field.